Parameter study for manufacturing an inner and outer cladding tube used in dual-cooled annular fuel

The design concept of dual-cooled annular fuel is focused on an advanced cooling geometry by applying inner and outer coolant channels in the fuel rod to increase power plant economy. Since dual-cooled annular fuel is contacted with the coolant in both inner and outer sides, two cladding tubes are needed for the inner and outer sides in the fuel, compared to a solid fuel. Thus, the properties in both the inner and outer claddings will be considered to meet the criteria of a dual-cooled annular fuel design. Regarding the design factor affecting fuel integrity and safety, the balance of creep deformation and irradiation growth between inner and outer claddings is a very important design factor. The microstructural factors such as recrystallization fraction and texture development must be coordinated to control the creep deformation and irradiation growth of zirconium alloy as a fuel cladding by controlling the manufacturing parameters. In order to setup the manufacturing parameters of the inner and outer claddings used for dual-cooled fuel, various samples are manufactured and tested. The manufacturing parameters contain the Q-value and annealing conditions, and the test items consist of a mechanical test, texture analysis, and corrosion test to evaluate the performance of the manufacturing processes. From this, the essential element factors to separately control the performance of the inner and outer claddings can be suggested.

► Dual-cooled annular fuel demands two claddings for inner and outer sides.
► Cladding performance has to similar between inner and outer cladding.
► Detailed manufacturing parameter to control the performance in both claddings was suggested.